Canada OKs construction of first licensed teeny atomic reactor

Built by 2028? Maybe. Powering homes? That’s another slip of paper entirely

Canadian nuclear regulators have approved an Ontario company's request to build a single small modular reactor (SMR) – the first such license issued in the country.

But with the chosen design yet to be operated anywhere in the world, it's best to take the news with a heap of salt. And we're not talking molten fuel/coolant salt.

The Canadian Nuclear Safety Commission (CNSC) on Friday granted Ontario Power Generation (OPG) a license to construct a single GE Hitachi BWRX-300 SMR at its Darlington New Nuclear Project site in Clarington, Ontario, just east of Toronto. 

Darlington, already home to an atomic power plant undergoing refurbishment to extend the life of four pressurized heavy-water fission reactors, has long been earmarked for new nuclear development. OPG has been preparing the site for some time, with utility lines already being run, and an on-site fabrication facility currently being built. 

While the current license only covers the construction of one unit, OPG's long-term plan calls for up to four BWRX-300 reactors at the site. Each unit is expected to generate up to 300 megawatts of electricity, and OPG claims that if all four are eventually built, the plant could power up to 1.2 million homes.

The BWRX-300 is a boiling-water fission reactor design that relies on natural circulation to move coolant through the core, reducing the need for pumps and enabling more passive safety features - at least on paper.

"The commission concluded that OPG is qualified to construct the reactor and will do so in a way that protects the health and safety of people and the environment," the CNSC said. 

The construction license issued by the CNSC authorizes OPG to build only one of its proposed four small modular reactors at the Darlington site, the CNSC noted, and it does not permit the operation of the unit.

"Authorization to operate the reactor would be subject to a future commission licensing hearing and decision, should OPG come forward with a license application to do so," the CNSC said. 

In addition to the lack of operational approval, the license includes several regulatory hold points - essentially mandatory checkpoints - that require OPG to obtain CNSC sign-off before progressing to key stages of construction.

OPG has said it expects the first unit to be completed by 2028, with electricity delivery starting in 2029. Construction of additional reactors, assuming they're ever licensed, would stretch into the 2030s, according to the utility.

Ambitious

If – and it's a big if, really – Canada gets this SMR built and running, it'll be the first one deployed outside of China or Russia, which would be no small feat. But as with most things nuclear, the gap between a construction license and flipping the switch on a grid-connected reactor is wide, winding, and filled with bureaucratic and technical potholes.

One of the biggest: GE Hitachi's BWRX-300 hasn't been built anywhere, let alone fired up. While it's further along than some paperware reactors, the compact design hasn't received full regulatory certification in the US, where it was designed. In Canada, the BWRX-300 has made it through phases one and two of the CNSC's Vendor Design Review. The CNSC told us that the review, which is optional, has nothing to do with the actual reactor certification process.

In other words, GE Hitachi's reactor isn't anywhere near design certified in Canada.

In the US, the only SMR design to clear the regulatory hurdle is NuScale's 50 MW model, which was approved by the US Nuclear Regulatory Commission in 2022. However, no commercial projects based on it have been successfully deployed to date.

We've asked GE for an update on the SMR's regulatory approval. 

So, whether OPG will succeed remains to be seen. Delays could result in OPG's project trailing Michigan's Palisades initiative, which intends to reignite a decommissioned nuclear power plant. Additionally, Holtec International plans to construct two SMR reactors at the Palisades site targeted for 2030. However, Holtec's SMR design has yet to receive full regulatory approval.

Also worth questioning is whether President Trump's sweeping tariffs will upset the project. While Canadian firms are involved in the construction of the BWRX-300 reactors, the design and fuel supply are managed by US-based GE Hitachi Nuclear Energy. In response to those tariffs, China has placed limits on exports of rare earth minerals, some of which are neutron absorbers used in fission control rods.

This reliance on US technology and enriched fuel has sparked discussions about energy sovereignty, especially considering that Darlington's existing pressurized heavy-water reactors are already based on a Canadian design and utilize domestically sourced natural uranium without the need for foreign enrichment.

As with most SMR projects, there are a lot of unanswered questions. We've reached out to OPG to get some answers. ®

Editor's note: This story was updated on April 9 to clarify the certification status of the BWRX-300 in Canada, following feedback from the Canadian Nuclear Safety Commission. As we noted originally, and today, GE Hitachi has yet to receive a design certificate for its reactor.